MRCOOL DIY Mini Split, Seriously, I Think...

[Browneye]

Re: Where to mount Mr. Cool

thanks for the reply, i should have been more clear.

the lineset will be run on the outside of the wall. even if i could squeeze the linset in between the 2x4s, i wouldn't

acknowledge on the disconnect and outdoor wire. i'll throw a 20amp fuse in there, and the line is to a dedicated 20amp breaker in the sub panel. the power wire from the disconnect to the compressor is a self contained/sheathed deal i picked up off amazon.

the outdoor unit will be mounted ~5' above the ground on a wall bracket.

thanks again for the post, you confirmed what i was thinking, even though my photo diagram sucked

Sounds good.

There has been a lot of back and forth discussion in here about fused or breaker'd power feed. Seems some of the interpretation of what is required is steeped in history and older electrical hardware that meets or exceeds those requirements. Specifically about a fused disconnect - it is clear from those in the know and from the code that a fuse can also be a AC rated breaker, either at the disconnect or in the main panel. We've also since found out that all breakers are now HVAC rated, it's where the industry went.

So if you have a fused disconnect that's great, just put one rated for the spec called out for on the UL label on the unit. I'm pretty sure the 12K unit needs a 20a fuse or breaker - I have one in my master suite on a 20a circuit.

An unfused or breakered disconnect is also fine as long as the main is the proper rating for both amperage and AC use - it would have to be something really old to not be HVAC rated.

You're gonna love the virtually silent ice cold air conditioning!

 

[MattT]

24KWh at 13 cents per KW equals $3.12 per hour to operate. How many hours per day do you think the compressor is running?

Hypothetically, if it ran 24/7, it would cost $2,246 per month !!

The guys mini split definitely isn't using 24kWh per hour. It sounds like that 24kWh number is for the week or maybe per day worst case. They pull roughly 1kWh per hour per ton running hard which drops off as they modulate down. When I checked one of my 1 ton units August last year it averaged 10kWh per day IIRC.

 

[GrantOpus]

I finally installed my 36K last weekend. Works great but do they ever shut off? Seems like both inside and outside unit are always on. I have it in “cool” mode and set at 79.

Should I be putting the unit in “auto” mode? It sounded like it would cycle between cool and heat if I did that.


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[Fueler]

I finally installed my 36K last weekend. Works great but do they ever shut off? Seems like both inside and outside unit are always on. I have it in “cool” mode and set at 79.

Should I be putting the unit in “auto” mode? It sounded like it would cycle between cool and heat if I did that.


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79 is cool? Daaang. where are you?


Auto works well for me. You won't even notice the change. It's subtle

 

[GrantOpus]

I’m in FL. I put it to 79 during the day and turn it down when I’m working in the shop. It is so much better to work out there now with the humidity low.


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[Fueler]

It's oft cussed and discussed but my own experience says leave it set where you want it and forget it. The auto mode will keep it righteous day or night.
It will likely be cheaper by a few pennies also.


Using different words: You will save nothing by fussing with the thermometer.

 

[Browneye]

I finally installed my 36K last weekend. Works great but do they ever shut off? Seems like both inside and outside unit are always on. I have it in “cool” mode and set at 79.

Should I be putting the unit in “auto” mode? It sounded like it would cycle between cool and heat if I did that.

The outside compressor unit shuts off when set temp is reached.
The inside air handler slows to a whisper but remains active, on, and ready to resume cooling.

The savings from setting the temp up when unneeded is offset by the extra energy used to cool to a lower set point. But I get it, we do the same thing in the house. When it cools off at night it gets shut off, use the on timer to get it going again later in the day.

"Auto" will engage heat if needed, so I switch to heat when it's actually needed. Cool mode for me.

The fan 'auto' setting is the most efficient. Turbo kicks it to high for max cooling. Be sure to set it back to 'auto'.

 

[Slowbra]

The outside compressor unit shuts off when set temp is reached.

The inside air handler slows to a whisper but remains active, on, and ready to resume cooling.



The savings from setting the temp up when unneeded is offset by the extra energy used to cool to a lower set point. But I get it, we do the same thing in the house. When it cools off at night it gets shut off, use the on timer to get it going again later in the day.



"Auto" will engage heat if needed, so I switch to heat when it's actually needed. Cool mode for me.



The fan 'auto' setting is the most efficient. Turbo kicks it to high for max cooling. Be sure to set it back to 'auto'.

I am curious on your perspective about the dry mode? From both an efficiency standpoint and ideal usage standpoint.

I’ve had my unit installed a few weeks and for about a week I ran it on dry mode during the day. It did a great job keeping it cool enough for me to work and dry. But I’m curious what’s the best time to use that ca other modes.

 

[GrantOpus]

The outside compressor unit shuts off when set temp is reached.

The inside air handler slows to a whisper but remains active, on, and ready to resume cooling.



The savings from setting the temp up when unneeded is offset by the extra energy used to cool to a lower set point. But I get it, we do the same thing in the house. When it cools off at night it gets shut off, use the on timer to get it going again later in the day.



"Auto" will engage heat if needed, so I switch to heat when it's actually needed. Cool mode for me.



The fan 'auto' setting is the most efficient. Turbo kicks it to high for max cooling. Be sure to set it back to 'auto'.

Thank you for your input.


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[WVBrady]

24KWh at 13 cents per KW equals $3.12 per hour to operate. How many hours per day do you think the compressor is running?

Hypothetically, if it ran 24/7, it would cost $2,246 per month !!

Hmm

His rate is 13 cents per Kilowatt-HOUR. KWh is a quantity of energy, just like a gallon of gasoline contains a quantity of energy. KW is a RATE at which you are using the energy, just as Gallons/hour is the rate at which you would be using the gasoline.

He said that he had a device that measured the usage of energy of 23KWh for one week; at 13 cents per KWh, that would be $3.12 per week, or $12.48 per month (at four weeks per month).

 

[Browneye]

His rate is 13 cents per Kilowatt-HOUR. KWh is a quantity of energy, just like a gallon of gasoline contains a quantity of energy. KW is a RATE at which you are using the energy, just as Gallons/hour is the rate at which you would be using the gasoline.

He said that he had a device that measured the usage of energy of 23KWh for one week; at 13 cents per KWh, that would be $3.12 per week, or $12.48 per month (at four weeks per month).

What a bargain, eh?
Seems like our two - a 12 and a 24, will bump our bill about $100 mid-summer. They run about 12 hours a day at least. Our primary rate is about 27cents, with a third tier we can occassionally get close to that is 42cents. Yeow!

Thank you for your input.

I am curious on your perspective about the dry mode? From both an efficiency standpoint and ideal usage standpoint.

I’ve had my unit installed a few weeks and for about a week I ran it on dry mode during the day. It did a great job keeping it cool enough for me to work and dry. But I’m curious what’s the best time to use that ca other modes.

I've used it a time or two, but we don't have a lot of humidity here in so-Cal. It's generally about 40-45%, so the benefit or air-feel would certainly be less than say, 85-95% RA.

I do notice when it is more humid the main one makes condensate twice as fast.
We collect condensate in a watering bucket for the patio plants and veg's. Free clean soft water!

I have read that the biggest change in environment for any air conditioned space is that the first reduction of RA feels like the biggest change - then the unit gradually and actually cools the air down, which takes much longer.

In super dry climes, like AZ, a swamp-cooler can really make it feel cooler. I've seen them and was surprised how well they work.

 

[GRivera]

I juggled with the lineset dilemma for months. I didn’t want to coil it up outside either and looked at all methods of running it to avoid that. However, I finally just ran it outside and placed the condenser far enough away to avoid the coil.

I’ll put a few bushes up and will never think about it again.

I did raise the unit off of the pad a bit higher than shown in the picture below to ensure there was plenty of airflow.

Nice install - what is the hard cover you used to shield the line assembly? Also, what is the distance vertically and horizontally for the outside portion of the lines?

 

[Slowbra]

Nice install - what is the hard cover you used to shield the line assembly? Also, what is the distance vertically and horizontally for the outside portion of the lines?

Thank you. I used the 4.5” Fortress brand lineset cover. It’s a nice brown color and good quality as far as I can tell.

The lineset goes down ~7.5’ and across ~14’

 

[GRivera]

Do you think a 3.5” line set would have fit?

 

[Slowbra]

Do you think a 3.5” line set would have fit?

I have the 36K system and the lineset (and drain) was a tight fit with the 4.5”. I think it would’ve been pretty tight with a 3.5” - especially the bends.

 

[GRivera]

One other thing I noticed looking through the service manual is only one fuse is shown for the 240v units. That's normal for the rest of the world but a North American 240v unit should have both legs fused. That may be why the importer specifed external fuses.

Do you know if the 24k units require 10/3 or 10/2 wire? I attached manual (page 17) and picture below. Looks like 10/2 but want to make sure...

https://cdn.iwae.com/media/manuals/mrcool/diyae-installation.pdf

 

[polizei1]

Alright finally bit the bullet.... Home Depot had the 24k DIY for $1,349. They wouldn't allow a military discount for online orders. Lowe's price matched and offered the 10%, plus free shipping to my house. $1,300 OTD!

Soooooo, now I need to know what else I need.

10/3 Liquidtight AC whip?
30-Amp AC disconnect?
30-Amp Cartridge Fuse?
10/3 from the main breaker to the disconnect?

 

[Browneye]

Do you know if the 24k units require 10/3 or 10/2 wire? I attached manual (page 17) and picture below. Looks like 10/2 but want to make sure...

https://cdn.iwae.com/media/manuals/mrcool/diyae-installation.pdf

You only need the two feed wires for the 240v and common ground.
10/2 has 3 wires in it.

IIRC 12g is fine for a 25a hvac circuit. 10 will work too, it's just harder to hook up - make sure your disco and breakers can accept the heavier wire.

Alright finally bit the bullet.... Home Depot had the 24k DIY for $1,349. They wouldn't allow a military discount for online orders. Lowe's price matched and offered the 10%, plus free shipping to my house. $1,300 OTD!

Soooooo, now I need to know what else I need.

10/3 Liquidtight AC whip?
30-Amp AC disconnect?
30-Amp Cartridge Fuse?
10/3 from the main breaker to the disconnect?

IIRC the 24K unit requires 25a circuit. 12g is okay for 25a HVAC.

I used plastic gutter with molded corners for line cover - $12:

 

[Browneye]

I think I posted this up-thread...but just to reiterate...
We collect the condensate water from our main unit to water patio plants and gardens. It fills a watering bucket and when overflows goes to a surface drain.
The water comes out at 32ppm as seen here - that's the same as we get out of our reverse osmosis drinking water filter. Our tap water starts at 475ppm. I read recently the epa limit is 500ppm. And it smells like chlorine, and the 5 micron pre-filter turns brown from rust sediment. Look how nice they are to provide safe drinking water. LOL

 

[LS6 Tommy]

I think I posted this up-thread...but just to reiterate...
We collect the condensate water from our main unit to water patio plants and gardens. It fills a watering bucket and when overflows goes to a surface drain.
The water comes out at 32ppm as seen here - that's the same as we get out of our reverse osmosis drinking water filter. Our tap water starts at 475ppm. I read recently the epa limit is 500ppm. And it smells like chlorine, and the 5 micron pre-filter turns brown from rust sediment. Look how nice they are to provide safe drinking water. LOL

Condensate water is distilled. Mom used it for decades in her iron. Just don't drink it.

Tommy

 

[Browneye]

Condensate water is distilled. Mom used it for decades in her iron. Just don't drink it.

Tommy

It's probly fine to drink, but since it's come off the cooling coils in the air handler it can pick up any dust and dirt that collects there as well.

I have a RO unit so I don't need it for drinking water, but my guess is running it through a 5 micron filter with carbon would make it safe.

On humid days that 2-ton unit will make some 4 to 6 gallons of water. It's incredible!

 

[LS6 Tommy]

It's probly fine to drink, but since it's come off the cooling coils in the air handler it can pick up any dust and dirt that collects there as well.

My point exactly.

Tommy

 

[clymer]

Hey all, just an update on my 24K unit. Been heating with this so far this fall season, works great for my little house. Installed a year and 1/2 ago, so far no issues. Anyone know of any threads where I can read about peoples experience with these things after several years? I am installing a larger multi-head deployment at a place I built in NH next year, and I am looking at other names -plumber up there said he has had luck with Haier, believe it or not, but I am thinking that maybe mitsubishi is the way to go for the high SEER rating for cold weather heating. I am not opposed to saving money again with the mr cool gear again, but that setup is going to be more involved so it won't be DIY.. Just want to know what the general feeling is out there for these things over longer periods of time

 

[polizei1]

IMO Mitsubishi is the #1 brand currently. If it's a dedicated system for a house, spend the money and get a good unit, especially a high efficiency model. They are also rated the best (I believe) in cold weather, I think down to -15F.

 

[stillnostrebor]

To add to this incredibly informative thread...

We installed a Mr Cool 36k unit in our 30'x40'x12' shop this spring. Shop is insulated to code for SW Missouri, no windows, two 8' square insulated OH doors, shaded most of the day. The minisplit worked flawlessly all summer keeping the shop cool and dry.

Slipping into winter now and switched over to heat, and about three days in the unit stopped working... fell dead on its face like no power. Tested good voltage all the way back to the inside appliance, and found all three factory terminals for the wiring that connects condenser and evaporator units completely loose, wires just floating. It was easy to find as the unit tried to start up as soon as I pulled the little cover that accesses the wires and touched the harness. Cut power, tightened the lugs, and it fired right up. Has been silently pumping heat into my shop since.

I'm super happy with the unit, and the ease of install, but wanted to share this tidbit with GJ, as I am probably not the only one who has received a unit with un-tightened harness connections from the factory. I didn't think to check these, as I didn't make their connection initially. Something to double check if you have one of these.

Purchased mine from Costco BTW... turned out to be the best bang for my buck at the time.

 

[Browneye]

Hey all, just an update on my 24K unit. Been heating with this so far this fall season, works great for my little house. Installed a year and 1/2 ago, so far no issues. Anyone know of any threads where I can read about peoples experience with these things after several years? I am installing a larger multi-head deployment at a place I built in NH next year, and I am looking at other names -plumber up there said he has had luck with Haier, believe it or not, but I am thinking that maybe mitsubishi is the way to go for the high SEER rating for cold weather heating. I am not opposed to saving money again with the mr cool gear again, but that setup is going to be more involved so it won't be DIY.. Just want to know what the general feeling is out there for these things over longer periods of time

If you're having pro-quotes see if one sells Daikin - also highly rated and not so high-budget as the Mitsubishi.

Make sure any savings for a seer rating will get made up in use. Sometimes the actual break-even for up front costs can take a dozen years to reach.

The comment about Mitz being a 'good unit' is true, but then MrCool isn't a 'bad unit' either as a presumption.

 

[kingnothing]

Images here: imgur.com/a/Q1TnHjP

Been following this thread for a while, and finally decided to buy the 12K unit from Costco. Can't post a real link to the images yet, sorry. The outside half seems a bit damaged but I'm not sure. Does this look ok, or should I return it? The inside portion seems fine.

 

[Browneye]

Images here: imgur.com/a/Q1TnHjP

Been following this thread for a while, and finally decided to buy the 12K unit from Costco. Can't post a real link to the images yet, sorry. The outside half seems a bit damaged but I'm not sure. Does this look ok, or should I return it? The inside portion seems fine.

Can't see an image...full url?

Up-thread you'll see I bought a scratch-n-dent from Ingrams - had to disassemble the compressor housing and straighten everything out. Worked out fine, and saved about $500.

 

[dcg9381]

It's probly fine to drink, but since it's come off the cooling coils in the air handler it can pick up any dust and dirt that collects there as well.

I have a RO unit so I don't need it for drinking water, but my guess is running it through a 5 micron filter with carbon would make it safe.

On humid days that 2-ton unit will make some 4 to 6 gallons of water. It's incredible!

I'm on "water collection" soon. Condensate is collected for use with the lawn - non-edible plants. Reading the interwebz, I find that some people indicate that this water is acidic (I find this unlikely), may contain lead and other trace metals, etc.
I can tell you that it works great with our plants.
I have zero plans to drink it - if I was to consider such, I'd have it run through a lab first, as I "suspect" that it may have dissolved metals....

 

[justinjoyal]

Hey all, just an update on my 24K unit. Been heating with this so far this fall season, works great for my little house. Installed a year and 1/2 ago, so far no issues. Anyone know of any threads where I can read about peoples experience with these things after several years? I am installing a larger multi-head deployment at a place I built in NH next year, and I am looking at other names -plumber up there said he has had luck with Haier, believe it or not, but I am thinking that maybe mitsubishi is the way to go for the high SEER rating for cold weather heating. I am not opposed to saving money again with the mr cool gear again, but that setup is going to be more involved so it won't be DIY.. Just want to know what the general feeling is out there for these things over longer periods of time

FYI, HSPF is what you should be looking at as far as heating is concerned.

Haier is OK but not great.

 

[polizei1]

So... just checking in, fired mine up for the first time today. I have it set to heat mode, 62* (lowest it will go), with the fan on auto. I'm planning to leave it like this all winter long unless you guys tell me otherwise. Are these settings good?

It was beautiful to be able to work in a nice environment!

 

[SALIV8]

Images here: imgur.com/a/Q1TnHjP

Been following this thread for a while, and finally decided to buy the 12K unit from Costco. Can't post a real link to the images yet, sorry. The outside half seems a bit damaged but I'm not sure. Does this look ok, or should I return it? The inside portion seems fine.

I copied and pasted your link and it worked good.

I agree the metal clips on top next to each other seem odd, but I don't own a mr cool hopefully someone else will compare theirs to yours.

The kinked clear tube is simply protecting the wire to that thermistor so that is not a problem imo.

The box looks super beat up. I'm surprised the fins are as straight as they are.

 

[kingnothing]

Can't see an image...full url?

Up-thread you'll see I bought a scratch-n-dent from Ingrams - had to disassemble the compressor housing and straighten everything out. Worked out fine, and saved about $500.

Yours was definitely in worse shape than mine. I PM'd you the images, let me know if that doesn't work. I didn't want to clutter the thread with 5 big images.

I finally found an image of the back of the 12k and I think this is actually how it's supposed to look so I'm probably fine. But if you want to take a look and let me know what you think that'd be great. Thanks!

 

[Browneye]

PM answered - I think you're good!
Install and go.

 

[kingnothing]

PM answered - I think you're good!
Install and go.

Great, thanks! Another question -- the installation manual says the outdoor unit should be "protected from prolonged periods of direct sunlight or rain", and then elsewhere it says to build a shelter if the unit is frequently exposed to heavy rain or snow. I live in Albuquerque so it doesn't snow often. Sometimes there are heavy rains (especially in July-August) but that's about it. It will be on the east side of the house so it'll be in direct sunlight a good portion of the day. No more than the main air conditioner for the house which is nearby though.

I saw that you built a sloped roof over your outside unit. Do you think I need to do that too? The outside unit will be on the other side of the wall from the inside unit, like yours, so I'll only need 7-8 feet of lineset.

 

[jjrbus]

Great, thanks! Another question -- the installation manual says the outdoor unit should be "protected from prolonged periods of direct sunlight or rain", and then elsewhere it says to build a shelter if the unit is frequently exposed to heavy rain or snow. I live in Albuquerque so it doesn't snow often. Sometimes there are heavy rains (especially in July-August) but that's about it. It will be on the east side of the house so it'll be in direct sunlight a good portion of the day. No more than the main air conditioner for the house which is nearby though.

I saw that you built a sloped roof over your outside unit. Do you think I need to do that too? The outside unit will be on the other side of the wall from the inside unit, like yours, so I'll only need 7-8 feet of lineset.

????? They put mini split outside units on roofs, how could they be kept out of the sun?

Most minis claim no less than 10 feet of lineset or can cause noise.

 

[SALIV8]

????? They put mini split outside units on roofs, how could they be kept out of the sun?

Most minis claim no less than 10 feet of lineset or can cause noise.

 

[bodydamage]

Going on the third winter with ours, so problems at all whatsoever. The phone app was a bit temperamental for a while, but the latest update appears to have fixed it. It does struggle when it gets down into the teens here. It still kicks out heat, you just have to turn it up a bit. We only use it on a very limited basis in the summer, but it seems to work just fine.

 

[Browneye]

Great, thanks! Another question -- the installation manual says the outdoor unit should be "protected from prolonged periods of direct sunlight or rain", and then elsewhere it says to build a shelter if the unit is frequently exposed to heavy rain or snow. I live in Albuquerque so it doesn't snow often. Sometimes there are heavy rains (especially in July-August) but that's about it. It will be on the east side of the house so it'll be in direct sunlight a good portion of the day. No more than the main air conditioner for the house which is nearby though.

I saw that you built a sloped roof over your outside unit. Do you think I need to do that too? The outside unit will be on the other side of the wall from the inside unit, like yours, so I'll only need 7-8 feet of lineset.

My two-ton unit sits on the south side of the house, in the weather, all day, 365 days a year. They make this recommendation for longest durability.

I have a gas-fired pool heater that you can no longer read the led display cuz it sits outside unprotected. Any outdoor appliance is going to fade and deteriorate faster if left unprotected.

I built the weather shield for my other unit so I could coil the lineset horizontally in it. Double win.

The MrCool DIY already have pre-built and connected 25' lineset so you don't have to worry about the noise comment. But you do have to decide what to do with excess lineset. The manufacturer does not recommend vertical coils as they can become a trap for the refrigerant oil and can starve your compressor. A lot of people do them that way anyway, we just don't know if they will have premature failure or not. I didn't want to chance it - only wanted to do this once. LOL

Anyway, if the unit fills up with snow it's not going to work very well. And that's the reason for the precautions. Or for flooding - it's an electric appliance that won't survive flooding. Rain drains out the bottom, same as heating mode condensate - there's even a drain tube option for the bottom of the compressor housing.

 

[3rdgendslmech]

I've got a question regarding the lineset routing. Can you run the lines inside vs. drilling a hole and having them exit the wall where the air handler is?